2014/04/26 by Masatoshi Imanishi, Kouichiro Nakanishi · 42 citations
Chemistry · Physics and Astronomy · #Active galactic nucleus #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Chemistry #Flux (metallurgy) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Infrared #Luminous infrared galaxy #Physics #Spectroscopy #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1088/0004-6256/148/1/9
published in The Astronomical Journal 148(1), 9 (Institute of Physics) · 27 pages, 11 figures, accepted for publication in AJ
arxiv created 2014/04/26 · openalex publication_date 2014/05/28 · arxiv updated 2015/06/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present the results of our ALMA Cycle 0 observations, using HCN/HCO + /HNC J = 4–3 lines, of six nearby luminous infrared galaxies with various energetic contributions from active galactic nuclei (AGNs) estimated from previous infrared spectroscopy. These lines are very effective for probing the physical properties of high-density molecular gas around the hidden energy sources in the nuclear regions of these galaxies. We find that HCN to HCO + J = 4–3 flux ratios tend to be higher in AGN-important galaxies than in starburst-dominated regions, as was seen at the J = 1–0 transition, while there is no clear difference in the HCN-to-HNC J = 4–3 flux ratios among observed sources. A galaxy with a starburst-type infrared spectral shape and very large molecular line widths shows a high HCN-to-HCO + J = 4–3 flux ratio, which could be due to turbulence-induced heating. We propose that enhanced HCN J = 4–3 emission relative to HCO + J = 4–3 could be used to detect more energetic activity than normal starbursts, including deeply buried AGNs, in dusty galaxy populations.